Radio-frequency (RF) circuits including passive RF sensing systems may be utilized for many applications such as surface acoustic wave (SAW) sensing. In these RF circuits, several RF interconnects that may include RF controlled impedance lines and antennas may require a signal conductive layer and a ground conductive layer. Typically, these RF circuits employing RF interconnects are fabricated though the use of microstrip transmission lines and/or patch antennas.
Microstrip transmission lines generally include a dielectric substrate having signal conductive layer positioned on a surface of the dielectric substrate and a ground conductive layer positioned on opposite surface of the dielectric substrate. The signal conductive layer and the ground conductive layer are electrically connected through via-holes in the dielectric substrate and interact with each other to create an electromagnetic wave that travels through dielectric substrate to create a RF signal. The performance of the microstrip transmission lines (RF circuits) may depend on various parameters including width of the microstrip transmission lines, the thickness of the dielectric substrate, and the relative dielectric constant of the material of the dielectric substrate. Though the performance of the microstrip transmission line (RF circuits) may be improved by increasing the thickness of the dielectric substrate, the potential limitations may exist with respect to the fabrication complexity and cost. For example, one of the major challenge in fabricating such RF interconnects may be creation of via-holes in a thick dielectric substrate.
There is a need for alternative configurations and processes for fabricating printed circuit assemblies such as RF interconnects, which provide simplified and cost-effective means of fabrication and improved reliability.